Q: The rule at our ASU is that a patient who received sedation should not drive after discharge, so patients are required to either have a ride or we will call a cab for them. They are instructed about this when they make their appointment and then again on the day of the procedure, emphasizing that even if they feel clear-headed that they may not actually be fit to drive.  I just found out that a patient I had done the anesthesia on had left on his own and that there had been a problem. Apparently, he had driven himself in and his wife was supposed to come and pick him and the car up, but when she called him to say that she was delayed at work he walked out without telling anyone and drove himself home. When he didn’t answer his phone the Head Nurse sent the cops to his house and he was passed out on the porch. EMS brought him to the ER and he was fine and Risk Management has already told me that I have no issue here because this all occurred after I signed him out to Recovery, but I’m actually not clear on how the hospital could be on the hook if he had had a bad outcome since he broke the rule.

Dr. Medlaw: What you are referring to is the legal doctrine of intervening superseding cause.

This goes back to the requirement that when a plaintiff is making a medical malpractice claim they must show that the alleged negligent act or omission was the proximate cause of the harm that they suffered – in other words, that it was the direct and uninterrupted cause of the injury.

This is a matter of fairness to the defendant.  Tort law operates on the premise that someone should be responsible for what they cause but we do not want plaintiffs setting up penumbras of claims that they want to assign to the defendant because of what the defendant did initially.

Therefore, if there are several negligent acts in the series of events that resulted in an injury a subsequent act by another defendant or by the plaintiff themselves may sever the causal link to the original defendant for some or all of the ultimate injury.

This would then be an “intervening superseding cause” of the injury – “intervening” because it happened between the original negligence and the injury, impinging on the connection between them, and “superseding” because it turned aside the original course of events to a different outcome.

The intervening superseding cause doctrine will apply if the subsequent negligent act or omission was (1) sufficient by itself to cause the injury, and (2) was not foreseeable to the first defendant.

Foreseeability is, as expected, an issue of reasonability. A defendant is not responsible to predict a rare event but, on the other hand, cannot claim that anything less than certainty was not foreseeable.

For example, suppose that a person who needs surgery because of prior malpractice then gets an infection due to inadequate antiseptic technique.  This second negligence would not separate the original defendant from the ultimately increased injuries because that there could be negligence in the surgery that their own negligence caused to be required is foreseeable.  In such a case the second doctor would be liable for the infection but the first doctor would be liable for the harm caused by both the original malpractice and the subsequent infection.

The exact mechanism of subsequent negligence does not have to be foreseeable if the general mechanism is.  An example of this would be a patient who is hospitalized because of malpractice who then falls out of bed because the nurse left the bed rail down and is further injured as a result.  That the nurse did so specifically because she rushed out due to news of a personal emergency would not be relevant, and only the fact that bed rails are known to sometimes be improperly left down would matter.

A serendipitous event, such as the ambulance carrying someone suffering from the effects of malpractice being in an MVA that further injures them, would come under this doctrine, though, because it would be considered unforeseeable.  That vehicles can crash into each other is certainly a known possibility but is too far a stretch to be chargeable to the original defendant.  In that situation the injured person could therefore sue the original doctor for the malpractice that put them in the ambulance but would have to sue the other driver for their further injuries.

In the situation at your ASU, the patient’s choice to leave and drive despite being made aware of the safety issues was definitely negligent.  It also met the first criterion for an intervening superseding cause because it was capable of causing the harm on its own.  However, it failed as to non-foreseeability because that someone might leave and drive despite the rule was actually fully foreseeable. The patient’s conduct therefore did not interrupt the causation from the hospital’s negligence in failing to keep an adequate eye on patients who should not leave and drive.

If the patient had suffered a lasting harm, or had harmed a third party while driving in an iatrogenically-impaired state, the causation would have rested solely on the hospital.  All that the hospital might have been able to do would  be to seek a percentage set-off  in damages because of the contribution of the patient’s own negligence.

This was definitely a canary in the negligence coal mine and the ASU should reinforce its monitoring of post-procedure patients because it will not be able to rely on a patient violating a rule to wait for a ride in limiting its own liability from a failure to prevent leaving and driving.